Inductor

ABSTRACT

An inductor includes a first core, a conducting wire, a second core and a first lead frame. There is an accommodating space formed on a first side of the first core and there is a recess portion formed on a second side of the first core, wherein the first side is opposite to the second side. The first core has a first height. The conducting wire is disposed in the accommodating space. The second core is disposed on the first side of the first core and covers the accommodating space. The first lead frame has an embedded portion embedded in the recess portion. The embedded portion has a second height. After embedding the embedded portion in the recess portion of the first core, a total height of the embedded portion and the first core is smaller than the sum of the first height and the second height.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an inductor and, more particularly, to aninductor adapted to be integrated with an integrated circuit (IC) chipby system-in-package (SIP) technology.

2. Description of the Prior Art

An inductor is a passive electrical component that can store energy in amagnetic field created by the electric current passing through it. Aninductor's ability to store magnetic energy is measured by itsinductance. Typically an inductor is a conducting wire shaped as a coil,the loops helping to create a strong magnetic field inside the coil dueto Faraday's Law of Induction. Inductance is an effect resulting fromthe magnetic field that forms around a current-carrying conductor whichtends to resist changes in the current. The number of loops, the size ofeach loop, and the material it is wrapped around all affect theinductance. For example, the magnetic flux linking these turns can beincreased by coiling the conductor around a material with a highpermeability such as ferrite magnetism.

So far there are various types of inductors disclosed in the prior arts.For example, a drum type of inductor is disclosed in Japanese patent No.3-83909, another drum type of inductor is disclosed in U.S. Pat. No.7,477,122, and a compact power semiconductor package with stackedinductor and integrated circuit die is disclosed in U.S. publishedapplication No. 20090160595. In general, most of the conventionalinductors are integrated with an IC chip by two manners depicted in thefollowing.

The first manner is that a lead is extended from a lower core of aninductor so as to be welded on a welding foot of a circuit board.However, in order to keep specific structure strength, the lower coremust have a specific thickness, such that the total height of theinductor integrated with the IC chip will increase.

The second manner is that an external lead frame is connected under alower core of an inductor so as to be welded on a lead frame of an ICchip. However, the height of the external lead frame will make the totalheight of the inductor integrated with the IC chip increase.

Thus, if the inductance has to be kept in a specific value, the totalheight of the conventional inductor integrated with the IC chip cannotbe reduced, such that it cannot be adapted to a thin design.

SUMMARY OF THE INVENTION

Therefore, one objective of the invention is to provide an inductor witha conducting wire embedded in a core. When the inductor is integratedwith an IC chip by system-in-package technology, the total height can bereduced effectively, such that an electronic product can be adapted to athin design.

Another objective of the invention is to provide an inductor utilizing alead frame to provide a platform for welding a conducting wire, so as toobtain high welding strength.

According to one embodiment, an inductor of the invention comprises afirst core, a conducting wire, a second core and a first lead frame. Anaccommodating space is formed on a first side of the first core and arecess portion is formed on a second side of the first core, wherein thefirst side is opposite to the second side. The first core has a firstheight. The conducting wire is disposed in the accommodating space. Thesecond core is disposed on the first side of the first core and coversthe accommodating space. The first lead frame has an embedded portionembedded in the recess portion. The embedded portion has a secondheight. After embedding the embedded portion in the recess portion, atotal height of the embedded portion and the first core is smaller thana sum of the first height and the second height.

According to another embodiment, an inductor of the invention comprisesa first core, a conducting wire, a second core and a first lead frame.An accommodating space is formed on a first side of the first core and arecess portion is formed on a second side of the first core, wherein thefirst side is opposite to the second side. A hole is formed on an edgeof the first core. The conducting wire is disposed in the accommodatingspace. The second core is disposed on the first side of the first coreand covers the accommodating space. The first lead frame has an embeddedportion and a welding platform, the embedded portion is embedded in therecess portion, and the welding platform is connected to the embeddedportion. One end of the conducting wire passes through the hole and iswelded on the welding platform.

According to another embodiment, an inductor of the invention comprisesa first core, a conducting wire, a second core and a first lead frame.An accommodating space is formed on a first side of the first core and arecess portion is formed on a second side of the first core, wherein thefirst side is opposite to the second side. A hole is formed on a cornerof the first core. The conducting wire is disposed in the accommodatingspace. The second core is disposed on the first side of the first coreand covers the accommodating space. The first lead frame has an embeddedportion embedded in the recess portion. One end of the conducting wirepasses through the hole and is welded on the embedded portion.

As mentioned in the above, since the invention embeds the conductingwire into the core, the total height can be reduced effectively when theinductor is integrated with an IC chip by system-in-package technology.Accordingly, the electronic product equipped with the inductor of theinvention can be adapted to a thin design. Furthermore, the inductor ofthe invention utilizes the lead frame to provide a platform for weldingthe conducting wire, so as to obtain high welding strength.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an assembly of an inductorand an IC chip package structure according to one embodiment of theinvention.

FIG. 2 is an exploded view illustrating the inductor shown in FIG. 1.

FIG. 3 is a front view illustrating the inductor shown in FIG. 1.

FIG. 4 is a perspective view illustrating an inductor according toanother embodiment of the invention.

FIG. 5 is an exploded view illustrating the inductor shown in FIG. 4.

FIG. 6 is a perspective view illustrating the inductor shown in FIG. 4from another view angle.

FIG. 7 is an exploded view illustrating the inductor shown in FIG. 6.

FIG. 8 is a front view illustrating the inductor shown in FIG. 4.

FIG. 9 is a perspective view illustrating the inductor shown in FIG. 4without the second core.

FIG. 10 is a schematic diagram illustrating an assembly of the inductorshown in FIG. 4 and an IC chip package structure.

FIG. 11 is a schematic diagram illustrating an inductor and a secondlead frame of an IC chip according to another embodiment of theinvention.

DETAILED DESCRIPTION

Referring to FIGS. 1 to 3, FIG. 1 is a schematic diagram illustrating anassembly of an inductor 1 and an IC chip package structure 3 accordingto one embodiment of the invention, FIG. 2 is an exploded viewillustrating the inductor 1 shown in FIG. 1, and FIG. 3 is a front viewillustrating the inductor 1 shown in FIG. 1. As shown in FIGS. 1 to 3,the inductor 1 comprises a first core 10, a conducting wire 12, a secondcore 14 and two first lead frames 16. The first core 10 or the secondcore 14 may be made of iron powder, ferrite, permanent magnet or othermagnetic materials. The shape of the first core 10 or the second core 14is not limited to rectangular as shown in the figures and may bedesigned in other shapes, such as circular, oval-shaped, polygonal, andsoon, according to practical applications. The conducting wire 12 maybea wire-wound coil wound by copper wire.

As shown in FIG. 2, an accommodating space 100 is formed on a first sideS1 of the first core 10 and four recess portions 102 are formed on asecond side S2 of the first core 10 (there are only three recessportions 102 shown in FIG. 2 due to the view angle), wherein the firstside S1 is opposite to the second side S2. In this embodiment, the fourrecess portions 102 are formed on four corners of the first core 10respectively, such that the area utilization ratio of the accommodatingspace 100 can be improved effectively. In this embodiment, each of thetwo first lead frames 16 has two opposite embedded portions 160, awelding platform 162 and a lead 164, wherein the welding platform 162 isconnected between the two embedded portions 160 and the lead 164 isextended from the welding platform 162. In practical applications, thefirst lead frame 16 may be formed by forging process.

To assemble the inductor 1, the conducting wire 12 has to be disposed inthe accommodating space 100 first. Afterward, the second sore 14 isdisposed on the first side S1 of the first core 10 and covers theaccommodating space 100. Then, the embedded portions 160 of each firstlead frame 16 are embedded in the recess portions 102 on the second sideS2 of the first core 10 correspondingly. In this embodiment, two holes104 are formed on two opposite edges of the first core 10 respectively,so two opposite ends of the conducting wire 12 can pass through theholes 104 and be welded on the welding platforms 162 of the first leadframes 16 respectively, so as to obtain high welding strength.

As shown in FIG. 3, the first core 10 has a first height H1 and theembedded portion 160 of the first lead frame 16 has a second height H2.After embedding the embedded portion 160 of the first lead frame 16 inthe recess portion 102 of the first core 10, a total height H0 of theembedded portion 160 and the first core 10 is smaller than a sum of thefirst height H1 and the second height H2.

As shown in FIG. 1, when the inductor 1 is integrated with the IC chippackage structure 3 by system-in-package technology, the first leadframes 16 can be used to form an air bridge and connected to electricalpads (not shown) of the IC chip package structure 3. In this embodiment,the IC chip package structure 3 may be manufactured by using anencapsulation gel to encapsulate an IC chip and lead frame thereof.Since IC chip package technology is well known by one skilled in theart, it will not be depicted in detail herein. As mentioned in theabove, since the total height H0 of the embedded portion 160 and thefirst core 10 is smaller than a sum of the first height H1 of the firstcore 10 and the second height H2 of the embedded portion 160 and theconducting wire 12 is embedded in the accommodating space 100 of thefirst core 10, the invention can satisfy the requirement of inductancewithout increasing the height of the inductor 1 and can improve theconnection between the IC chip package structure 3 and the inductor 1.

In this embodiment, the lead 164 of the first lead frame 16 has alongitudinal shape and extends downward so as to be connected toelectrical pad of the IC chip package structure 3. However, in anotherembodiment, a lead of the IC chip package structure 3 may be extendedupward so as to be connected to the lead frame 16. Furthermore, anexternal lead may be used to connect the first lead frame 16 of theinductor 1 and the electrical pad of the IC chip package structure 3. Inother words, the connecting manner between the first lead frame 16 andthe IC chip package structure 3 may be designed based on practicalapplications and not limited to the embodiment shown in the figures.

Referring to FIGS. 4 to 9, FIG. 4 is a perspective view illustrating aninductor 5 according to another embodiment of the invention, FIG. 5 isan exploded view illustrating the inductor 5 shown in FIG. 4, FIG. 6 isa perspective view illustrating the inductor 5 shown in FIG. 4 fromanother view angle, FIG. 7 is an exploded view illustrating the inductor5 shown in FIG. 6, FIG. 8 is a front view illustrating the inductor 5shown in FIG. 4, and FIG. 9 is a perspective view illustrating theinductor 5 shown in FIG. 4 without the second core 54. As shown in FIGS.4 to 9, the inductor 5 comprises a first core 50, a conducting wire 52,a second core 54 and two first lead frames 56. The first core 50 or thesecond core 54 may be made of iron powder, ferrite, permanent magnet orother magnetic materials. The shape of the first core 50 or the secondcore 54 is not limited to rectangular as shown in the figures and may bedesigned in other shapes, such as circular, oval-shaped, polygonal, andsoon, according to practical applications. The conducting wire 52 maybea wire-wound coil wound by copper wire.

As shown in FIGS. 5 and 7, an accommodating space 500 is formed on afirst side S1 of the first core 50 and four recess portions 502 areformed on a second side S2 of the first core 50, wherein the first sideS1 is opposite to the second side S2. In this embodiment, the fourrecess portions 502 are formed on four corners of the first core 50respectively, such that the area utilization ratio of the accommodatingspace 500 can be improved effectively. In this embodiment, each of thetwo first lead frames 56 has two opposite embedded portions 560 and alead 564, wherein the lead 564 is extended from the embedded portion560. In practical applications, the first lead frame 56 may be formed byforging process.

To assemble the inductor 5, the conducting wire 52 has to be disposed inthe accommodating space 500 first. Afterward, the second sore 54 isdisposed on the first side S1 of the first core 50 and covers theaccommodating space 500. Then, the embedded portions 560 of each firstlead frame 56 are embedded in the recess portions 502 on the second sideS2 of the first core 50 correspondingly. In this embodiment, two holes504 are formed on two opposite corners of the first core 50respectively, so two opposite ends of the conducting wire 52 can passthrough the holes 504 and be welded on the embedded portions 560 of thefirst lead frames 56 respectively (as shown in FIG. 9), so as to obtainhigh welding strength.

As shown in FIG. 8, the first core 50 has a first height H1′ and theembedded portion 560 of the first lead frame 56 has a second height H2′.After embedding the embedded portion 560 of the first lead frame 56 inthe recess portion 502 of the first core 50, a total height H0′ of theembedded portion 560 and the first core 50 is smaller than a sum of thefirst height H1′ and the second height H2′.

Referring to FIG. 10, FIG. 10 is a schematic diagram illustrating anassembly of the inductor 5 shown in FIG. 4 and an IC chip packagestructure 7. As shown in FIG. 10, when the inductor 5 is integrated withthe IC chip package structure 7 by system-in-package technology, thefirst lead frames 56 can be used to form an air bridge and connected tothe IC chip package structure 7. As mentioned in the above, since thetotal height H0′ of the embedded portion 560 and the first core 50 issmaller than a sum of the first height H1′ of the first core 50 and thesecond height H2′ of the embedded portion 560 and the conducting wire 52is embedded in the accommodating space 500 of the first core 50, theinvention can satisfy the requirement of inductance without increasingthe height of the inductor 5 and can improve the connection between theIC chip package structure 7 and the inductor 5.

In this embodiment, the lead 564 of the first lead frame 56 is designedas T-shaped and extends downward so as to be connected to the IC chippackage structure 7. As shown in FIG. 10, the recesses 700 correspondingto the leads 564 maybe formed on the IC chip package structure 7. Theleads 564 can be embedded and then welded in the recesses 700 so as toimprove welding strength. However, in another embodiment, a lead of theIC chip package structure 7 may be extended upward so as to be connectedto the lead frame 56. Furthermore, an external lead may be used toconnect the first lead frame 56 of the inductor 5 and the IC chippackage structure 7. In other words, the connecting manner between thefirst lead frame 56 and the IC chip package structure 7 may be designedbased on practical applications and not limited to the embodiment shownin the figures.

Referring to FIG. 11, FIG. 11 is a schematic diagram illustrating aninductor 5′ and a second lead frame 70 of an IC chip according toanother embodiment of the invention. As shown in FIG. 11, the secondlead frame 70 of an IC chip (not shown) can be extended toward the firstlead frame 56′ of the inductor 5′ so as to be connected to the firstlead frame 56′. In this embodiment, the second lead frame 70 comprisestwo opposite U-shaped lead frames. However, in another embodiment, thesecond lead frame 70 maybe designed as ring-shaped. That is to say, theshape of the second lead frame 70 can be designed based on practicalapplications and not limited to the embodiment shown in the figure.Moreover, the second lead frame 70 has an electrical pad 702, which canbe electrically connected to the IC chip. It should be noted that thesecond lead frame 70 may have more than one electrical pad 702 withsheet shape or other shapes and the electrical pad may be located at themiddle, side or any position of the second lead frame 70. That is tosay, the second lead frame 70 is not limited to the embodiment shown inFIG. 11.

It should be noted that the first core 10 shown in FIG. 2 can bereplaced by the first core 50 shown in FIG. 5, the first core 50 shownin FIG. 5 can be also replaced by the first core 10 shown in FIG. 2, andit depends on practical applications.

Compared to the prior art, since the invention embeds the conductingwire into the core, the total height can be reduced effectively when theinductor is integrated with an IC chip by system-in-package technology.Accordingly, the electronic product equipped with the inductor of theinvention can be adapted to a thin design. Furthermore, the inductor ofthe invention utilizes the lead frame to provide a platform for weldingthe conducting wire, so as to obtain high welding strength.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention.

1. An inductor comprising: a first core, an accommodating space beingformed on a first side of the first core, a recess portion being formedon a second side of the first core, the first side being opposite to thesecond side, the first core having a first height; a conducting wiredisposed in the accommodating space; a second core disposed on the firstside of the first core and covering the accommodating space; and a firstlead frame having an embedded portion embedded in the recess portion,the embedded portion having a second height; wherein after embedding theembedded portion in the recess portion, a total height of the embeddedportion and the first core is smaller than a sum of the first height andthe second height.
 2. The inductor of claim 1, wherein the conductingwire is a wire-wound coil.
 3. The inductor of claim 1, wherein the firstlead frame has a welding platform connected to the embedded portion, ahole is formed on an edge of the first core, one end of the conductingwire passes through the hole and is welded on the welding platform. 4.The inductor of claim 3, wherein the first lead frame has a leadextended from the welding platform.
 5. The inductor of claim 1, whereina hole is formed on a corner of the first core, one end of theconducting wire passes through the hole and is welded on the embeddedportion.
 6. The inductor of claim 1, wherein the first lead frame has alead extended from the embedded portion.
 7. The inductor of claim 1,wherein the recess portion is formed on a periphery of the first core.8. The inductor of claim 1, wherein the inductor is adapted to beintegrated with an integrated circuit chip by system-in-packagetechnology, the integrated circuit chip comprises a second lead frameextending toward the first lead frame, such that the second lead frameis able to be electrically connected to the first lead frame.
 9. Theinductor of claim 8, wherein the second lead frame is ring-shaped. 10.The inductor of claim 8, wherein the second lead frame comprises twoopposite U-shaped lead frames.
 11. An inductor comprising: a first core,an accommodating space being formed on a first side of the first core, arecess portion being formed on a second side of the first core, thefirst side being opposite to the second side, a hole being formed on anedge of the first core; a conducting wire disposed in the accommodatingspace; a second core disposed on the first side of the first core andcovering the accommodating space; and a first lead frame having anembedded portion and a welding platform, the embedded portion beingembedded in the recess portion, the welding platform being connected tothe embedded portion, one end of the conducting wire passing through thehole and being welded on the welding platform.
 12. The inductor of claim11, wherein the first core has a first height, the embedded portion hasa second height, after embedding the embedded portion in the recessportion, a total height of the embedded portion and the first core issmaller than a sum of the first height and the second height.
 13. Theinductor of claim 11, wherein the inductor is adapted to be integratedwith an integrated circuit chip by system-in-package technology, theintegrated circuit chip comprises a second lead frame extending towardthe first lead frame, such that the second lead frame is able to beelectrically connected to the first lead frame.
 14. The inductor ofclaim 13, wherein the second lead frame is ring-shaped.
 15. The inductorof claim 13, wherein the second lead frame comprises two oppositeU-shaped lead frames.
 16. An inductor comprising: a first core, anaccommodating space being formed on a first side of the first core, arecess portion being formed on a second side of the first core, thefirst side being opposite to the second side, a hole being formed on acorner of the first core; a conducting wire disposed in theaccommodating space; a second core disposed on the first side of thefirst core and covering the accommodating space; and a first lead framehaving an embedded portion embedded in the recess portion, one end ofthe conducting wire passing through the hole and being welded on theembedded portion.
 17. The inductor of claim 16, wherein the first corehas a first height, the embedded portion has a second height, afterembedding the embedded portion in the recess portion, a total height ofthe embedded portion and the first core is smaller than a sum of thefirst height and the second height.
 18. The inductor of claim 16,wherein the inductor is adapted to be integrated with an integratedcircuit chip by system-in-package technology, the integrated circuitchip comprises a second lead frame extending toward the first leadframe, such that the second lead frame is able to be electricallyconnected to the first lead frame.
 19. The inductor of claim 18, whereinthe second lead frame is ring-shaped.
 20. The inductor of claim 18,wherein the second lead frame comprises two opposite U-shaped leadframes.